1. Field of the Invention
The present invention relates to an RF converter for converting video and audio signals received from a video tape recorder (VTR), a video disc apparatus or the like, into an RF television broadcast signal, including a surface acoustic wave (SAW) band pass filter.
2. Description of the Prior Art
Conventionally, for improving VTR playback picture quality, a so-called video enhancer has been employed to reduce deterioration in resolution due to a loss of high frequency components of a video signal in video-recording or dubbing. Such a video enhancer, for instance, as disclosed on page 75 of the book entitled "NHK Home video Technique" edited by Nippon Hoso Kyokai and published in April, 1980, performs a high band boost of the video signal using, for example, a simple RC circuit or LC circuit. This conventional video enhancer has the disadvantage that the amplitude characteristic, namely, the frequency response characteristic is compensated, but the phase characteristic (group delay characteristic) is deteriorated, and thereby ringing is produced on the TV screen. Another system has also been proposed including a circuit called a "video corrector," which emphasizes the contour by operating the passing signal and the reflected signal of the delay line. However, this circuit, for instance, as disclosed on page 58 of Vol. 31 December/1983 of the magazine "Television Technique" published by Denshi Gijutsu Shuppan, has the disadvantage that the circuit configuration is complicated and a large number of parts are required.